I had this email conversation with Brian Adams of ADPerformance and I'm having trouble understanding the details. Below is the condensed version of the emails between us.
Link to the rotation assembly in question:
http://www.adperformance.com/index.php? ... cts_id=673
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Rick Said:
I need more info about your Scat 4340 Forged Competition Rotating Assembly for $969.00.
- Scat part number for the crankshaft?
- Is this crank internal or externally balanced?
- I can't find specs for the piston options. What ring spec are used? Are any "file to fit" rings?
- Mahle Coated with Rings.....are these pistons Forged?
Thanks!
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Brian Said:
Thank you for your inquiry.
The crank part number can be different if a 6" rod is selected but the base level is 4-350-3750-5700 and is external balance. The 6" rod option is a 4-350-3750-6000 and is internal balance. Both are unbalanced kits at that price.
The basic kit is crank, rod and pistons as listed, no rings are included. Most of our plasma moly ring sets are available as a file fit.
Mahle's pistons are forged, the only piston we carry that is not is a KB.
Brian Adams
http://www.ADperformance.com
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Rick Said:
Thanks for getting back with me!!!
Could you confirm that the crank for 5.7 rods is externally balanced???
When I search the Scat catalog for 4-350-3750-5700 I find the following.
Part Number: 4-350-3750-5700
Short Number: 435050
Description: 350 2-PC REAR SEAL
Stroke: 3.750
Rod Length: 5.700
Rod Pin: 2.1000
Weight: 52
Tech Notes: Internal balance
When selecting "Mahle Coated, with Rings" piston option, are the rings "File to Fit" or "Standard"???
Thanks again!
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Brian Said:
I'll defer it to the manufacture but speaking from experience a short counterweighted Scat 3.75 stroke can be difficult to balance internal.
Mahle's rings are a file fit ring generally.
Brian Adams
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My questions are:
- Is there a reason why the rotating assemble with 6" rods would be easier to balance??? Would it be the lighter pistons with the shorter compression height???
- What does he mean by "short counterweighted" and does he make sense???
I would like to have an internally balanced engine, if I ever have to replace a balancer or flex plate it won't be necessary to disassemble the engine to re-balance. Also I'm leaning towards the 5.7" rods so the wrist pin does not end up in the ring groove, this will be a street engine.
If I buy the individual components what do I need to know??? It seem I've read about having trouble balancing randomly selected components. I'm reading Reher-Morrison "Championship Engine Assembly" Book, maybe all my questions will be answered if I just keep reading.
Any input is greatly appreciated.....thanks!!!
Rick
Link to the rotation assembly in question:
http://www.adperformance.com/index.php? ... cts_id=673
--------------------------------------------------------------------------
Rick Said:
I need more info about your Scat 4340 Forged Competition Rotating Assembly for $969.00.
- Scat part number for the crankshaft?
- Is this crank internal or externally balanced?
- I can't find specs for the piston options. What ring spec are used? Are any "file to fit" rings?
- Mahle Coated with Rings.....are these pistons Forged?
Thanks!
--------------------------------------------------------------------------
Brian Said:
Thank you for your inquiry.
The crank part number can be different if a 6" rod is selected but the base level is 4-350-3750-5700 and is external balance. The 6" rod option is a 4-350-3750-6000 and is internal balance. Both are unbalanced kits at that price.
The basic kit is crank, rod and pistons as listed, no rings are included. Most of our plasma moly ring sets are available as a file fit.
Mahle's pistons are forged, the only piston we carry that is not is a KB.
Brian Adams
http://www.ADperformance.com
--------------------------------------------------------------------------
Rick Said:
Thanks for getting back with me!!!
Could you confirm that the crank for 5.7 rods is externally balanced???
When I search the Scat catalog for 4-350-3750-5700 I find the following.
Part Number: 4-350-3750-5700
Short Number: 435050
Description: 350 2-PC REAR SEAL
Stroke: 3.750
Rod Length: 5.700
Rod Pin: 2.1000
Weight: 52
Tech Notes: Internal balance
When selecting "Mahle Coated, with Rings" piston option, are the rings "File to Fit" or "Standard"???
Thanks again!
--------------------------------------------------------------------------
Brian Said:
I'll defer it to the manufacture but speaking from experience a short counterweighted Scat 3.75 stroke can be difficult to balance internal.
Mahle's rings are a file fit ring generally.
Brian Adams
--------------------------------------------------------------------------
My questions are:
- Is there a reason why the rotating assemble with 6" rods would be easier to balance??? Would it be the lighter pistons with the shorter compression height???
- What does he mean by "short counterweighted" and does he make sense???
I would like to have an internally balanced engine, if I ever have to replace a balancer or flex plate it won't be necessary to disassemble the engine to re-balance. Also I'm leaning towards the 5.7" rods so the wrist pin does not end up in the ring groove, this will be a street engine.
If I buy the individual components what do I need to know??? It seem I've read about having trouble balancing randomly selected components. I'm reading Reher-Morrison "Championship Engine Assembly" Book, maybe all my questions will be answered if I just keep reading.
Any input is greatly appreciated.....thanks!!!
Rick